A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. / The reliability of using isotropically consolidated specimens in the laboratory determination of liquefaction characteristics of cohesionless sands, as is common practice today, is evaluated. Two series of triaxial tests involved the conventional undrained loading of isotropically and anisotropically consolidated specimens. The third series of tests utilized anisotropically consolidated specimens loaded by following special undrained stress paths. Test results revealed that liquefaction characteristics obtained from isotropically and anisotropically consolidated specimens are different. The effective angles of friction mobilized at peak shear stress and at steady state were greater for anisotropically consolidated specimens. Loading stress path is seen to have no effect on the liquefaction characteristics derived from conventional loading of anisotropically consolidated specimens. The critical stress ratio line is observed to be the line determining the initiation of liquefaction so that any stress path attempting to cross this line, regardless of direction of approach, immediately shows strain-softening behavior leading to liquefaction. / AC 2018

The Electricity Distribution Industry (EDI) in South Africa is in the process of restructuring into six Regional Electricity Distributors (REDs). This would entail the merging of the national electricity utility, Eskom Distribution with municipalities to consolidate skills and to improve on efficiencies. This integration would involve the assimilation of not only physical assets but also various organisational cultures into a separate organisation responsible for supplying electricity services within its designated geographical area. A separate challenge facing Eskom is an intensive capital expansion program to increase generation capacity which will require a committed workforce to execute. Organisational culture has been regarded as leading to greater productivity and generating commitment to the values and philosophies of the organisation. The purpose of the research was to determine whether there was a significant relationship between the organisational culture, organisational commitment and employee performance in Eskom Southern Region. In order to achieve this purpose a survey was undertaken (N=83) which measured perceptions regarding the existing organisational culture, preferred organisational culture as well as organisational commitment. Performance rating scores were linked to each respondent and were obtained from the performance management process of Eskom Southern Region. The main findings of this research can be summarised as follows: • The dominant existing organisational culture in Eskom Southern Region is the power culture, while the dominant preferred organisational culture is the achievement culture. • There is a significant organisational culture gap between the existing and the preferred organisational culture in Eskom Southern Region. • The dominant organisational commitment within Eskom Southern Region is affective commitment together with normative commitment. • The findings related to the employee performance include: o A slight but significant negative relationship was measured between the existing achievement culture and employee performance. o No significant relationships were measured between the preferred cultures and employee performance. o No significant relationships were measured between the organisational commitment scales and employee performance. • The findings pertaining to the relationship between organisational culture and organisational commitment can be stated as follows: o A significant positive linear relationship between the existing achievement culture and affective commitment was measured. A strong, significant negative linear relationship between the existing power culture and the affective commitment was also measured. o No significant relationships were measured between the preferred organisational cultures and organisational commitment. o The organisational culture gap has a significant effect on the organisational commitment of employees. • The findings pertaining to the relationship between the biographical variables and the organisational culture, organisational commitment and employee performance can be stated as follows: o There exists a strong significant relationship between the years of service and the existing organisational culture scales. o No significant relationships exist between the preferred organisational culture scales and any of the biographical variables. There was a common agreement across all respondents on the preferred organisational culture. o A significant relationship was found between organisational commitment and the number of people supervised. o A slight but significant positive linear relationship between the age of respondents and employee performance ratings was measured. It can therefore be concluded that the type of organisational culture has a significant impact on the level of affective commitment of the employees within Eskom Southern Region. No significant positive relationship was found between organisational commitment and organisational performance in Eskom Southern Region.

Thesis (M.Sc. (Hydrogeology))--University of the Witwatersrand, Faculty of Science, School of Geosciences, 2017. / Hartbeespoort Dam, the source of irrigation and potable water for the local community of Hartbeespoort area is a vulnerable water resource. The aim of this research was to evaluate the interaction between dam water and groundwater as well as characterise the hydrochemical data from metals and tritium. The former was done through the application of environmental isotopes and the implementation of a long term water balance, while the latter used hydrochemical data to define the spatial distribution of metals and tritium. The results indicated that the dam water is separated from the groundwater in winter. Two sources of mixing were recognized to have occurred downstream of the dam in 2015 but not in the Hartbeespoort dam area. These were identified as artificial through the runoff of agricultural water that was abstracted from the dam and through the pumping of water near the fault. Higher than normal tritium concentration indicated that contamination comes through the Crocodile River after the fault connecting the river to Pelindaba, the nuclear power generation plant south of Hartbeespoort Dam in the Broederstroom area. The Crocodile River showed that the contamination of water by lead, 22.11ppb in summer and 3.8 ppb in winter, and cadmium,2.2 ppb in winter. The Magalies River feeds the dam with copper. All metals accumulate at the dam wall and settles in the sediment, diluting the downstream water. Boreholes near the dam and spring along the fault are vulnerable to contamination. The water balance estimation resulted 18 345 472m3, with a 3.9% error, gain of water to the dam from the groundwater greater than the amount exiting the dam to through groundwater. The groundwater entering the dam is estimated to be 32 517 704m3. The groundwater exiting the dam is estimated at 14 172 232m3. The difference in groundwater showed a decrease of 10 000 000m3 over the 15 year period from 1st October 2000 until the 30th September 2015. Consequently, these results show an increased stress placed on the groundwater presumably due to an increase in groundwater abstraction from agriculture and the expanding mining area. / GR2018

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016. / The presence of estrogenic hormones in the environment has been a subject of concern in recent years; they have been classified as “emerging pollutants” and may pose a potential risk for human consumption. Hormones have been detected in ground and surface water at low concentrations. These compounds contaminate the surface and ground water via waste water treatment plants (WWTP) and may elicit endocrine disruption to organisms. Because these compounds are available at low concentration, robust analytical methods are required to quantify these compounds in water and environmental samples. The common method for the analysis of hormones in water samples is Gas Chromatography (GC) coupled to Mass Spectrometer (MS). The challenge with GC-MS is the required lengthy derivatisation step that involves toxic chemicals. The first part of this case study was to develop a method to determine trace concentrations of the Estrone (E1), 17α-Estradiol (E2α), 17 β-Estradiol (E2β) and 17α-Ethinylestradiol (EE2) hormones using Ultra-Fast Liquid Chromatography Mass Spectrometry (UFLC-MS-MS). Using the developed method, the second part of the case study was to determine the concentrations of the hormones in raw and potable water samples from the Vaal River catchment area in the South of Johannesburg, South Africa. Analytes were extracted by solid phase extraction (SPE C18 Sorbent, 200 mg/6mℓ cartridges) and subjected to Ultra-Fast Liquid Chromatography coupled to Mass Spectrometer (UFLC-MS-MS) for identification and quantification. Optimum SPE parameters were 1000 mℓ of sample percolated, at flow rate of 10 mℓ/min, sample pH of above 7, 7.5 mℓ of methanol as elution solvent followed by solvent reduction to 250 μℓ. The limits of quantification were in a range of 0.24 to 0.32 ng/ℓ for all analytes. Accuracy was 95.6, 93.8, 97.6 and 100.9% for 17α-Ethinylestradiol, 17α-Estradiol, 17β-Estradiol and estrone, respectively. In raw water samples taken during the rainy wet season, estrone was detected at concentrations of 0.90 and 4.43 ng/ℓ. However, drinking water samples no presence of hormones with the exception of M-B12 sample point where the estrone amount of 2.88 ng/ℓ was detected. This is potentially due to fact that conventional water treatment plants are able to remove the compounds during water purification process depending on the concentration levels. / LG2017

Bibliography: pages 177-183. / The dissertation is concerned with the production of a systematic analysis of HSRC research reports into mathematics education in South Africa between 1970 and 1980. Drawing on the theoretical language of Dowling (1995), the analysis focuses on the (re)production of voice and message in the reports. This entails an analysis of positioning strategies that il1ark out voices in the texts and distributing strategies that distribute message across voices. Voices include bureaucratic, academic, teacher and learner voices and knowledge and practices that constitute message distributed to voices relate to mathematical knowledge, pedagogic knowledge and curriculum innovation practices. Positioning and distributing textual strategies with respect to learner and teacher sub-voices are related to the (re)production of theories of instruction that constitute models of acquirers, transmitters and pedagogic contexts and define pedagogic competence in particular ways. The (re)production of theories of instruction in turn are related to the reproduction of social relations in the broader society. It is hoped that the analysis illustrates the generality of Dowling's language for analysing texts. The substantive focus of the study is the analysis of the reports and the language developed in the analysis is used to make some suggestive comments about current mathematics curriculum development in South Africa. It is hoped, in particular, that the focus in this study on discourses in mathematics education in South Africa in the 1970s will contribute to the documenting of the history of mathematics curriculum development in South Africa.

Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The emergence and re-emergence of viral human pathogens from wildlife sources in the recent past has led to increased studies and surveillance of wildlife for potentially zoonotic agents in order to gain a better understanding of the pathogens, their sources as well as events that may lead to viral emergence. Of the >1407 known human pathogens, 13% are classified as emerging or re-emerging, and 58% as zoonotic; 37% of the (re-)emerging and 19% of the zoonotic pathogens are RNA viruses, accounting for the majority of recently emerged infectious diseases with a zoonotic origin, such as HIV, Ebola, Hendra, Nipah, Influenza and SARS. This study focusses on potentially zoonotic viruses hosted by rodents (Muridae family), shrews (order previously known as Insectivora/Soricomorpha, now reclassified as Eulipotyphla) and bats (order Chiroptera). Rodents and bats represent the largest (~40%) and second largest (~25%) mammalian orders and both occur on every continent except Antarctica. Together, the three mammalian orders investigated represent the most relevant potential sources of new zoonoses. In this study I investigated the occurrence of astroviruses, arenaviruses, coronaviruses and hantaviruses in South African small mammal species belonging to the orders mentioned above. These viruses have either been implicated in recent emerging zoonotic events or are considered to have the potential to cause cross-species transmissions resulting in a zoonotic event. In the first part of the study specimens collected from various bat, rodent and shrew species were screened for viral sequences by broadly reactive PCRs; positive samples were characterised by sequencing and sequence analysis. A separate part of the study focussed on hantavirus disease in humans: a seroprevalance survey was conducted to determine the presence of hantavirus antibodies in the local population. Additionally, acutely ill patients with potential hantavirus disease were tested in an attempt to identify possible acute infections and define clinical hantavirus disease in South Africa. Screening of rodent and shrew specimens resulted in the identification of eight novel arenavirus sequences. Seven of the sequences are related to Merino Walk virus, a recently identified South African arenavirus, and the eighth sequence represents a novel lineage of Old World arenaviruses. Screening of bat specimens resulted in the identification of highly diverse novel astrovirus and coronavirus sequences in various South African bat species, including the identification of a viral sequence closely related to the recently emerged Middle East Respiratory Syndrome coronavirus. While the study did not identify hantavirus infections in any of the acutely ill patients, it found seroprevalences similar to those observed in Europe and West Africa. The results obtained highlight the importance of small mammals in the emergence of potential zoonoses and further reinforce the importance of viral surveillance of relevant wildlife species. Further in-depth studies of naturally infected reservoir host populations are required in order to gain a better understanding of virus-host dynamics and the events that lead to virus emergence. / German Research Foundation (DFG) (project number: KR1293/9-1/13-1) / The Polio Research Foundation and the NHLS Research / Harry Crossley Foundation, the Polio Research Foundation and Stellenbosch University for granting scholarships and bursaries for PhD.

Umkhonto we Sizwe (MK) was a military organization dominated by black Africans. Although it is not generally associated with Indian South Africans, who form a minority in the country, there were Indian MK members. This thesis explores the way in which Indian MK members reconciled aspects of their ethnic identity with their membership of MK. It explores the experiences of two generations of members: those born between 1929 and 1944 and those born between 1960 and 1969. In particular it looks at whether they experienced tensions between their ethnic and political identities. It explores what set these Indian South Africans apart from the rest of the Indian South African community that did not join MK. It also looks at what significant differences there were between different generations of Indian MK members. The research results show that the first generation MK members believe that their MK activities were „the highest form of passive resistance‟. An explanation for this way of referring to their activities could be that this was a way of reconciling tensions between their ethnic and political identities. The first generation was also very critical of the Indian SA community. This could be because they still feel part of this community despite having a strong political consciousness that is different from most of the community. It was found that some of the features that set Indian MK members apart from other Indian South Africans were that they were not raised in very religious households and occupied a fairly low rather than „middle man‟ economic position. In addition, members of the first generation of MK members were raised in comparatively multi-racial areas. Both generations made the decision to join MK because of Indian role models. There were some marked differences between the two generations of MK veterans. Most notably, the younger did not see their activities as in line with passive resistance and they also displayed more ambivalence about their ethnic identities.

Hierdie studie handel oor die ontwikkeling van geleenthede in Europa en Suid-Afrika vir analfabeet-volwassenes om te leer lees en skryf. Teoretiese aspekte van geletterdheid soos omskrywings van die begrippe geletterdheid en ongeletterdheid is ondersoek. Twee benaderings tot die voorsiening van geletterdheid, naamlik die relatiewe benadering en die absolute benadering is beskryf. Die doelwitte van geletterdheid behels onder meer die bereiking van lewensideale, die verkryging van mag en persoonlike ontwikkeling. Verskeie strategiee vir geletterdheidsonderrig soos die die voorsiening van fundamenteel-opvoedkundige strategie, die funksionele strategie, die bewusmakingstrategie en die massaveldtogstrategie is ondersoek. Die invloed van sosiale, politieke, ekonomiese, geografiese, godsdienstige en onderwysfaktore asook van die boekdrukkuns op die verspreiding van lees- en skryfvaardighede is beskou. Daar is ook ondersoek ingestel na die rol van verskillende betrokkenes by die voorsiening van geletterdheidsonderrig in Europa en Suid-Afrika soos die staat, nie-staatsorganisasies, kerke, vakbonde, industriee, privaatinisiatiewe, universiteite en biblioteke. / This thesis investigates the development in Europe and South Africa of opportunities for illiterate adults to learn to read and write. Theoretical aspects concerning the defining of concepts, the two approaches namely the absolute and relative, the aims of literacy and the attainment of ideas of empowerment and personal development were discussed. An investigation is done of the various strategies in the provision of literacy campaigns. These include the fundamental educational, the functional, the awareness and the mass campaign strategies. The influence of social, political, economical, geographical, religious and educational factors is explored in conjunction with the role of the printing press and distribution of reading and writing material. The role of various parties involved in the provision of literacy education in Europe and South Africa is considered. This includes the state, non-governmental organizations, churches, unions, industry, private initiatives, universities and libraries. / Educational Foundations / D. Ed. (Historiese Opvoedkunde)

Thesis (PhD)-- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Schizophrenia is a phenotypically heterogeneous disorder believed to have a strong genetic component. Limiting its clinical heterogeneity by means of subtyping may help to shed light on some of the genetic underpinnings of the disease. This study describes the application of factor analysis (FA), latent class analysis (LCA) and factor mixture modeling in a sample of 734 Xhosa-speaking schizophrenic subjects using factor analytically derived variables previously identified in an independent sample of this population. LCA was performed on the following 8 SANS and SAPS items identified by preliminary exploration of the data: eye contact, auditory hallucinations, global hallucinations score, global delusions score, grooming, affective non-responsiveness, spontaneous movement, and commenting voices. A four class model provided the best fit. Classes 1 and 2 were characterized by predominantly positive and predominantly negative symptoms, respectively, class 3 by both positive and negative symptoms and class 4 by few or absent symptoms. A history of cannabis use or abuse increased the probability of a subject being allocated to class 1, while being male made a person more likely to be included in class 2. Factor mixture modelling was performed by first using latent class analysis, then factor analysis and then the factor mixture analysis were done. The fit among these three types were then investigated. The results show that factor mixture modelling uncovered a heterogeneous latent variable structure that fits the data well with the latent classes capturing distinct positive symptom/behaviours and factors capturing severity variations. This study, the first to report on the latent class structure of schizophrenia in a sample of patients from a sub-Saharan African population, supports the universality of specific latent classes across ethnic boundaries. The results further support reports that gender, sibpair status and cannabis use may influence the phenomenology of schizophrenia. The identification of subgroups may represent an intermediate step in the search for endophenotypes of schizophrenia. / AFRIKAANSE OPSOMMING: Skisofrenie is „n psigiatriese steuring met „n heterogene fenotipe en „n vermoedelik sterk genetiese vatbaarheid. Ten einde die lig te werp op die genetiese onderbou van skisofrenie word gepoog om die kliniese heterogenisiteit te beperk deur middel van subgroepering. Hierdie studie beskryf die gebruik van latente klas analise (LKA) in „n groep van 734 Xhosa-sprekendes met skisofrenie. Die LKA word baseer op die gebruik van veranderlikes wat deur middel van faktor analise op simptome in „n onafhanklike studiegroep van Xhosa-sprekendes met skisofrenie verkry is. Die LKA is gedoen op die volgende 8 “SAPS” en “SANS” veranderlikes wat deur voorlopige ondersoek van die data ge-indentifiseer is: oogkontak, gehoorshallusinasies, globale hallusinasie telling, globale waantelling, selfversorging, affektiewe nie-responsiwiteit, spontane beweging en stemme wat kommentaar lewer. „n Vierklas oplossing het die beste passing getoon. Klas 1 en 2 is gekenmerk deur oorwegend positiewe en negatiewe simptome onderskeidelik, klas 3 het beide positiewe en negatiewe simptome gehad en klas 4 het baie min of geen simptome getoon nie. „n Geskiedenis van kannabis gebruik of misbruik het die kans verhoog dat die individue in klas 1 gevind sou word, terwyl manlike geslag as veranderlike die kanse verhoog het vir allokasie in klas 2. Faktor mengsel modelering is gedoen deur eers „n latent klas analise te voltooi, gevolg deur „n faktor analise, en laastens „n factor mengsel analise. Die passing tussen die drie analises is daarna evalueer. Faktor mengsel modelering toon „n heterogene latente klas struktuur wat voldoen aan die passingsvereistes. Die latente klasse blyk spesifieke positiewe simptome/gedrag te verteenwoordig, terwyl die factor grad van erns variasie aandui. Hierdie studie is die eerste om die latente klas struktuur van skisofrenie in „n subsahara-Afrika populasie, die Xhosa, te beskryf. Die resultate onderstreep die universialiteit van die latente struktuur van skisofrenie se simptome oor etniese grense heen. Verder ondersteun die resultate die moontlike rol van geslag, aangetaste sibstatus en kannabis gebruik in skisofrenie se fenomenologie. Die identifisering van die subgroepe mag „n intermediêre stap in die soektog vir endofenotipes van skisofrenie verteenwoordig.

In most countries, as many as 15 to 25% of the adult population have raised blood pressure. People with hypertension, and even those with mild elevation of blood pressure, are at an increased risk of cardiovascular disease, whether or not the symptoms are present. The risk of serious cardiovascular disease varies greatly among individuals and is also determined by a variety of concomitant risk factors other than the level of blood pressure. Hypertension develops as a result of disturbances of the body's blood pressure regulating system. The biological activity of the renin-angiotensin systems results from a series of specific enzymatic cleavages leading to the generation of angiotensin II, a potent vasoconstrictor. In the treatment of hypertension, inhibition of the angiotensin converting enzyme is established as one modern therapeutic principle. Angiotensin converting enzyme inhibitors act by inhibiting the conversion of angiotensin I to angiotensin II. The in vitro assay, developed by ELBL and WAGNER (1991) for the detection of angiotensin converting enzyme inhibitors in plant extracts was successfully established during this study. Plants used by traditional healers in South Africa for the treatment of high blood pressure were investigated for their antihypertensive properties, utilizing the established angiotensin converting enzyme assay. Twenty plants were investigated for their angiotensin converting enzyme inhibitory activity. The highest inhibition (97%) was obtained by Adenopodia spicata leaves. A further seven plants exhibited an inhibition greater than 70% and five more over 50%. Plants exhibiting inhibition levels greater than 50% were further tested for the presence of tannins in order to eliminate possible false positives. The leaves of Tulbaghia violacea were chosen for bioassay-guided fractionation in an attempt to isolate the active compound(s). Serial extractions were made of ground Tulbaghia violacea leaves using polar to non-polar solvents to establish the solvent giving optimum extraction of the active compound(s). Distilled H2O was selected as the extractant and a bulk extract was performed on 0.7 kg ground leaves. The extracted residue was partitioned against butanol, fractionated using cation exchange resin chromatography, Sephadex ® LH-20 and high performance liquid chromatography. Fractions collected after each purification step were assayed using the angiotensin converting enzyme assay. Fractions exhibiting high levels of angiotensin converting enzyme inhibition were selected for further purification. The active fraction from the final high performance liquid chromatography step used in this study requires further attention in order to purify and identify the active compound(s). The chromatographic and chemical properties of the compound(s) present in the isolated active fraction are discussed. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.